PORTSMOUTH, N.H. -- Tennessee Congresswoman Marsha Blackburn will consider running for president in 2016 -- if she sees an opportunity to do so, an aide to the 7th District Republican told RealClearPolitics. Blackburn is scheduled to be one of the speakers at a New Hampshire Republican rally this weekend but was not previously known to be mulling a White House bid. "If there's a door to kick down, she's willing to kick it down," the aide, who spoke on the condition of anonymity, said. "These are the kinds of events you go to -- test the waters, and see what...